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dopplerite sapropel

A variety of sapropel that contains much humic acid. Tomkeieff

dore

Gold and silver bullion that remains in a cupelling furnace after the lead
has been oxidized and skimmed off. Syn:dore bullion

dore bullion

See:dore

dore metal

See:dore silver

dore silver

Crude silver containing a small amount of gold, obtained after removing
lead in a cupelling furnace. Syn:dore bullion; dore metal.

dornick

a. A piece of rock of approx. fist size.
b. A boulder of iron ore.

Dorr mill

A tube mill designed for operation as a closed-circuit wet-grinding unit.
See also:tube mill

Dorr rake classifier

A mechanical classifier consisting of an inclined settling tank and a
rake-type conveying agitating mechanism. Feed introduced at the low end of
the tank flows over a distributing apron toward the high end of the tank.
The heavier materials of sand size settle into the rake zone and are raked
up the slope and out the tank; slime and finer sands are carried over the
rear wall in suspension. Taggart, 2

Dosco miner

A heavy, crawler-tracked, 200-hp (149-kW) cutter loader designed for
longwall faces in seams over 4-1/2 ft (1.37 m) thick, and takes a buttock
5 ft (1.52 m) wide. The maximum cutting height is 7-1/2 ft (2.29 m).
Dimensions: length 17-3/4 ft (5.41 m), width 4-1/2 ft (1.37 m), and height
3-3/4 ft (1.14 m). The cutterhead consists of seven cutter chains mounted
side by side and can be moved up and down radially to cut the coal from
roof to floor. It delivers the coal onto the face conveyor by a short
cross conveyor. Capacity is more than 400 st (363 t) per machine and more
than 4 st (3.63 t) output per worker per shift. Nelson

dose

a. A special charge used in a blast furnace, designed to cure furnace
troubles. Fay
b. The amount of ionizing radiation energy absorbed per unit mass of
irradiated material at a specific location, such as a part of the human
body. Measured in reps, rems, and rads. Lyman

dot chart

a. A graphic aid used in the correction of station gravity for terrain
effect, or for computing gravity effects of irregular masses. It can also
be used in magnetic interpretation. AGI
b. A transparent graph-type chart used in the calculation of the gravity
effects of various structures. The dots on the chart represent unit areas.
AGI

double

In rotary drilling, two pieces of drill rod left fastened together during
raising and lowering. Also called couple; couplet. Nichols, 1

double

A. One of several terms (or letter symbols) used to designate
medium-quality drill diamonds. Long

double-acting pump

Scot. A pump that discharges at both forward and backward stroke.

double-acting ram

See:two-way ram

double-action press

A press handling two operations each revolution. It carries two rams, one
inside the other, so actuated that one motion immediately follows the
other. Crispin

double-action pump

A pump whose water cylinders are equipped with intake and discharge valves
at each end; hence liquid is delivered by the pump on both the forward and
the backward strokes of the pump piston. Long

double bank

a. To take up a claim parallel with and adjoining another claim containing
an auriferous vein or deposit. Fay
b. Working with double sets or relays of persons. Fay

double block

a. A pair of multiple-sheave blocks reeved with rope or lines; a block and
tackle. Long
b. Two pulleys or small sheaves mounted on a single shaft within a frame
or shell. Long

double-burned

Burned at a high temperature. This does not mean two firings. AISI

double-burned dolomite

a. Dolomite, with additions of oxides of iron, burned at a high
temperature. This does not mean two firings. ARI
b. Clinkered dolomite. AISI